Thinking about starting red and have some questions.
 

How hard is it to get a group? What classes is the server lacking? What classes just suck at pvp? What classes over populate the server?

Dark elf warrior IMO

Make a gnome paladin you will thank me later. It is in high demand lay of hands will be a life savor for that anti-Gank pvp action. Why gnome? Size and quickness with keys will allow you to allude enemies and swing down with veroicity.

Wouldn't start as melee without decent gear (except Bard)
Druids/Wizards good start, because not gear-dependent and can port.
Any class good at pvp if prepared and well-played.
Lots of Wizards and SKs on the server already, popular PVP classes.
I would start on a weekend, peak time, when more low-level groups going.
Once you get to 20s, usually one group rolling in your lev range for xp.

SK best class IMO, you can solo and own in PVP all the way to 60.

We have a few banding together for some playtime tomorrow night if you're interested. Make whatever ya want. Thinking Gfay area to start.

I started last month and got 50 recently. I only grouped with like 2 clerics between 1-50 so I guess that is the least played but who knows. Finding groups was not that difficult during prime time EST and on weekends. Only hair in the soup is the twinked griefers in CB and MM or Unrest every now and then but the group XP bonus more than makes up for this in my opinion and at times they even provided an entertaining break from the XP grind. It's been a great time so far.